1. Field of the Invention
The present invention relates to a slatted apron and in particular to a slatted apron used as a movable protective cover for machines.
2. Description of Related Art
In the prior art, various types of movable covers for machines are known. These covers are used to, e.g., protect the machine against the chips produced in processing and against coolant required in processing, in order to enhance the service life of the machine, prevent damage to sensitive parts of the machine, ensure reliability of the machine, prevent excessive soiling of the machine, etc.
One type of a movable protective cover for a machine is a telescopic cover. This telescopic cover may be used for various purposes in various constructional types.
For example, a telescopic cover 10 in the configuration shown in FIG. 6 may be used as a spindle cover for a spindle 20 which is movable in the direction of arrows Y in FIG. 6, or may be used in the configuration shown in FIG. 7 as a foundation plate cover movable in the direction of arrows X in FIG. 7.
A like telescopic cover 10 does, however, present various drawbacks. For one thing, the telescopic cover 10 is generally comprised of steel so as to present a very high weight if used for large machines requiring a large-size protective cover, thus resulting in an increased expenditure of force on the moving mechanism of, for example, spindle 20. (Telescopic covers are customarily also only used at low moving speeds owing to their weight.) This additional expenditure of force must be taken into consideration when designing the moving mechanism of spindle 20 in order to eliminate additional sources of malfunction, and results in excessive energy input of the moving mechanism of spindle 20, resulting in increased operational costs of the machine. In order to reduce the expenditure of force, the telescopic covers 10 are generally guided or held, respectively, by sliders or rollers (not shown).
In order to prevent chips or the like from penetrating between the individual components 10a of the telescopic cover 10, it is moreover necessary to provide at one end 10b of components 10a a stripper (not shown) preventing such penetration of chips or the like. It is furthermore difficult to use these telescopic covers 10 in cases where it is required to move, for example, a spindle 20 not only in one but in two directions. Finally the manufacturing expenditure is comparatively high owing to the many different components, e.g., the variously sized single components 10a of the telescopic cover 10, the sliders or rollers etc., and the telescopic cover 10 is thereby altogether rendered expensive.
Another possibility of a protective cover for a machine is shown in FIGS. 8 and 9. This configuration is a so-called slatted apron 30. This slatted apron 30 is comprised only of two different single components, a slat or link 30a, and a link connector 30b. This slatted apron 30 presents various advantages over the above mentioned telescopic cover 10. For example, the slatted apron 30, the links 30a of which are preferably comprised of aluminum and the link connectors 30b thereof preferably of polyurethane, have a lower weight in comparison with the telescopic cover 10. Moreover in the case of the slatted apron 30 there is the possibility of simply deflecting it by means of a deflection device 40 (cf. FIG. 9). Moreover the slatted apron 30 may just as easily be rolled up by means of a reeling device 50. Accordingly, the slatted apron 30 quite readily offers the option of adapting it to the respective demands put to a protective cover, and it is also very easily possible in the case of the slatted apron 30 to provide a protective cover for a machine, which is suitable for two different directions of movement of, for example, a spindle of the machine. Articulated aprons 30 equally allow for very high moving velocities of up to 100 m/min as a result of their comparatively low weight
The slatted apron 30 as shown in FIGS. 8 and 9 does, however, present the following drawbacks.
Due to an intermediary zone 60 (cf. FIG. 8) between respective adjacent links 30a, there is the possibility of chips or the like accumulating on surfaces of the link connector 30b connecting the links 30a. In particular, there accordingly exists the possibility of chips or the like entering into a connection zone 70 of a link 30a and a link connector 30b and jamming or becoming wedged therein. As a result of the chips or the like, the useful life of the slatted apron 30 is reduced because, for example, the link connector 30b may be damaged by the chips etc. Moreover there is a possibility--where the slatted apron 30 is designed such that the links 30a and the link connector 30b extend in the vertical direction and the direction of movement of the slatted apron 30 is in the horizontal direction--of chips entering into guide means (not shown) attached to the bottom side in the direction of movement of the slatted apron 30 and also becoming jammed or wedged there, with the result that jolting movements of the slatted apron 30 may occur, or in a worst case the movement of the slatted apron 30 will be inhibited entirely.